If you are spending that much for a full rebuilt stroker motor, I'd go ahead and replace everything I possibly could on the engine and around it. New plugs & plug wires, new distributor cap & rotor, new engine & transmission mounts or reinforce them with urethane, new fuel lines, new fuel filter, refurbish/clean/benchmark the injectors (if its not carbed), clean the A/F meter with MAF cleaner, clean the inside of the throttle body or upgrade to a larger one, new thermostat, new heating lines, new radiator hoses, new upgraded alternator (or have the current one checked/cleaned), new/rebuilt starter. But thats just me and what I did and I didn't have too tight a budget at the time, and I hadn't been in a hurry to finish my project so I accrued the parts over a couple months.
I'd also flush the steering rack and put in new fluid, new grease everywhere, new boots if it needs them.
I'd forget about the stock clutch fan and get an electric fan kit and possibly build a shroud for it or adapt a stock 280zx plastic shroud for that stock look. Your radiator should be fine...fix any bent fins, flush it and clean it inside and out to make sure there are no leaks and if it goes bad later its not hard to replace on a Z with the engine in. If you want to refresh the look Eastwood sells thin radiator specific paint that doesn't retain heat.
The flywheel bolts should be fine, I haven't heard of those being a weak point and I know Tony D said he used regular L28 flywheel bolts on one of his builds. I'm not sure about the clutch, it really depends on how much power the engine is making after the rebuild...a "Stage 1" may not even be strong enough if its making enough power/torque...better to ask your builder that if he is familiar with L-series engines and has built strokers before.